Method of selectively removing conductive material

Abstract

An electrolyte solution, methods, and systems for selectively removing a conductive metal from a substrate are provided. The electrolyte solution comprising nanoparticles that are more noble than the conductive metal being removed, is applied to a substrate to remove the conductive metal selectively relative to a dielectric material without application of an external potential or contact of a processing pad with a surface of the substrate. The solutions and methods can be applied, for example, to remove a conductive metal layer (e.g., barrier metal) selectively relative to a dielectric material and to a materially different conductive metal (e.g., copper interconnect) without application of an external potential or contact of a processing pad with the surface of the substrate.

What is claimed is: 
     
       1. An electrolyte composition, comprising:
 a solvent having a dielectric constant of less than 40; and 
 nanoparticles selected from the group consisting of colloidal carbon, glassy carbon, silver, platinum, nickel-chromium, conductive oxides, and engineered colloids or catalysts. 
 
     
     
       2. The electrolyte composition of  claim 1 , wherein the solvent comprises an ionic liquid. 
     
     
       3. The electrolyte composition of  claim 1 , wherein the solvent comprises a hydrofluoric acid/glacial carboxylic acid solution. 
     
     
       4. The electrolyte composition of  claim 1 , wherein the solvent comprises a solution of an alcohol and a salt dissolved in the alcohol. 
     
     
       5. The electrolyte composition of  claim 4 , wherein the salt dissolved in the alcohol is selected from the group consisting of a salt of chloride, fluoride, succinate and citrate. 
     
     
       6. The electrolyte composition of  claim 4 , wherein the salt dissolved in the alcohol is selected from the group consisting of ammonium salts and potassium salts. 
     
     
       7. The electrolyte composition of  claim 4 , wherein an amount of the salt dissolved in the alcohol is at saturation. 
     
     
       8. The electrolyte composition of  claim 1 , wherein the nanoparticles comprise about 0.01% by weight to 10% by weight based on a total weight of the electrolyte composition. 
     
     
       9. An electrolyte composition, comprising:
 a hydrofluoric acid/alcohol solution having a dielectric constant of less than 40; and 
 nano articles selected from the group consisting of colloidal carbon, glassy carbon, silver, platinum, gold, nickel-chromium, conductive oxides, and engineered colloids or catalysts. 
 
     
     
       10. The electrolyte composition of  claim 9 , wherein the nanoparticles comprise about 0.01% by weight to 10% by weight based on a total weight of the electrolyte composition. 
     
     
       11. The electrolyte composition of  claim 9 , wherein the hydrofluoric acid/alcohol solution comprises a ratio of hydrofluoric acid:alcohol of from about 5:1 to about 50:1. 
     
     
       12. An electrolyte composition, comprising:
 a glacial carboxylic acid/hydrofluoric acid solution having a dielectric constant of less than 40; and 
 nanoparticles selected from the group consisting of colloidal carbon, glassy carbon, silver, platinum, gold, nickel-chromium, conductive oxides, and engineered colloids or catalysts. 
 
     
     
       13. The electrolyte composition of  claim 12 , wherein the nanoparticles have a particle size of about 0.001 μm to 5 μm. 
     
     
       14. The electrolyte composition of  claim 12 , wherein the nanoparticles comprise about 0.01% by weight to 10% by weight based on a total weight of the electrolyte composition. 
     
     
       15. The electrolyte composition of  claim 12 , wherein the glacial carboxylic acid is selected from the group consisting of acetic acid, butanoic acid and propionic acid. 
     
     
       16. An electrolyte composition, comprising:
 nanoparticles selected from the group consisting of colloidal carbon, silver, and platinum; and 
 a solvent having a dielectric constant of less than 40 and selected from the group consisting of a hydrofluoric acid/alcohol solution, a hydrofluoric acid/glacial carboxylic acid solution, a dissolved salt/alcohol solution, and an ionic liquid. 
 
     
     
       17. A system for removing a conductive metal selectively relative to a dielectric material on a substrate, the system comprising:
 a carrier for supporting the substrate; 
 a device for dispensing an electrolyte composition; and 
 a source of the electrolyte composition, the electrolyte composition comprising nanoparticles selected from the group consisting of colloidal carbon, glassy carbon, silver, gold, platinum, nickel-chromium, conductive oxides, and engineered colloids or catalysts in a solvent having a dielectric constant of less than 40 and selected from the group consisting of a hydrofluoric acid/alcohol solution and a hydrofluoric acid/glacial carboxylic acid solution, the electrolyte composition configured to remove the conductive metal selectively relative to the dielectric material on the substrate without an applied potential. 
 
     
     
       18. A planarizing apparatus, comprising:
 a support for a processing pad proximal to a substrate on a carrier; 
 actuating assemblies for moving the carrier, the support for the processing pad or both; 
 a source for dispensing an electrolyte composition for contact with the substrate; and 
 a source of the electrolyte composition, the electrolyte composition comprising nanoparticles in a solvent having a dielectric constant of less than 40, the nanoparticles selected from the group consisting of colloidal carbon, glassy carbon, silver, platinum, nickel-chromium, conductive oxides, and engineered colloids or catalysts. 
 
     
     
       19. The planarizing apparatus of  claim 18 , wherein the solvent having a dielectric constant of less than 40 comprises an ionic liquid. 
     
     
       20. The planarizing apparatus of  claim 18 , wherein the solvent having a dielectric constant of less than 40 comprises a dissolved salt/alcohol solvent.